Coating apparatus



Dec. 26, 1939. K|RCHNER 2,184,348

' comma APPARATUS Filed Oct. 27, 1932 2 Sheets-Sheet 1 ATTORNEY Dec.26,1939? H. P. KIRCHNER ET AL 2 I COATING APPARATUS Filed Oct. 27, 19:522 Sheets-Sheet 2 INVENTORS.

. v I HENRY P.K\RCHNER RoMlE L. MELTOH BY RAYMOND c. BENNER A TT0RNEYPatented Dec- 26, 19 39 COATING APPARATUS Henry P. Kirchner, Romie L.Melton, and Raymond C. Bonner, Niagara Falls, N. Y., assignors, by mesneassignments, to The Carborundum' pany, Niagara Falls, N.-Y., acorporation of Delaware Application October 27,4932, Serial 140.539.8367 Claims. (01. 91-18) The present invention relates to apparatus for themanufacture of granular coated webs of such materials as paper, cloth,or the like, and more especially to an electromagnetic apparatus forsecuring an inclined orientation of the abrasive particles.

We have found that if abrasive granular material containing orconsisting principally of elongated grains is applied to a backing web.such as paper or cloth, with the elongated grains inclined to the paperor cloth, superior cutting or abrasive properties are given to theabrasive paper or cloth. This'is believed to be due' to the action ofthe inclined elongated grains in cutting into the material to be abradedsomewhat after the manner of inclined saw teeth. The present inventionrelates particularly to a machine for electromagnetically securing suchinclination of the elongated grains of abrasive by reference to theaccompanying drawings inwhich:

Figure l is a diagrammatic side elevation of one form of apparatusconstructed in accordance with our invention;

Figure 2 is an enlarged view of a part of Fi ure 1;

Figure 3 is a view similar to Figure 2 but show ing a part of theapparatus adjusted to a different position;

Figure 4 is another enlarged view illustrating, in part, another form ofapparatus; and -Figure 5 is a diagrammatic side elevation of stillanother form of apparatus.

Referring first to Figure 1, this drawingshows means A for holding anddispensing a roll 2 of the web P; means B for applying adhesive to oneface of the web P; means C for angularly applying granular material tothe adhesive side of the web P; means D for causing a preliminary set ofthe adhesive; and means'E for drawing the web through the coatingapparatus and into a dry'mg chamber.

The means A for holding and dispensing the web P comprises, as is shownin the drawings, a frame i that supports the roll 2 of web P; am idlerroll 3 for guiding the web; printing rolls 4 and 5 for marking the webwith anydesired legend or identification; and an idler roll I forguiding the web.

The adhesive applying means B.comprise, as-

shown in the drawings, idler rolls 8 and 9 for guiding the web; a roll Hpositioned to dip into a pan l2 of adhesive; a roll l3 for maintainingcontact between the web P and the roll II; a. drum l5 and an adhesivedistributing brush l6 positioned above the said drum l5; and an idlerroll l8 for guiding the web as it is brought from the distributingbrush.

The means for applying granular material.

to the web P comprises, as shown in the drawings, idler rolls I9 and 20forguiding and positioning the web; a'magnet 26 with pole pieces 28 and29, so designed as to set up a distributed magnetic field which isrelatively weak -at the end where the-web enters and of graduallyincreasing-intensity at the opposite end, andwhich is adjustable bothangularly and vertically with respect to the idler rolls i9 and 20; anendless feed belt 4| positioned between the pole pieces 28 and 29 andsupported by the pulleys 42, 42a, 43 and 43a; and variable speed drivingmeans 44 for operating the feed belt 4la ll of these parts'being mountedon 'acradle 50 which is adapted for rotation about the axis 40. Means Calso includes a unit comprising a graimhopper .35 with an adjustablegate 36 and a roll 31 for dispensing the granular material to the feedbelt 4i which may, if desired, be mounted independently of the cradle50.

The means D for causingt'he adhesive to acquire a preliminary setcomprises, as shown in the drawing, an idler roll 49 and a fan blower 48for supplying a large volume of air at a low velocity to the adhesiveand granular coated side of the web P;

The means E for moving the web P through the- In the normal operationofthe apparatus il-.

lustrated inFlgure 1 a roll of the uncoated web P, such as paper orcloth,is rotatably mounted on the frame -I- and the web is threaded overthe roll 3 and between the printing rolls 4 and and thence in contactwith the idler rolls 1,

8 and 9 to the pressure roll l3 and the adhesive roll II. The adhesiveroll ll dips into liquid adhesive contained in the adhesive l2 and,

on the upward movement of travel of the roll H, a layer of adhesive isapplied to the web.

The adhesively coatedmaterial P passes be I: which the adhesive and amaghetic field set up between the pole pieces 28 and 29 of the magnet26.

Granular particles are distributed from the grain hopper 35 onto thegrain feed belt ll, which moves through the magnetic field parallel tothe web P and in the same direction, as shown in an enlarged view asFigure 2. The field of magnet 28 energizes the :granular particles,causing them to become, in eijfect, miniature magnets with poles attheir extreme ends or inother words, in such a manner that theirmagnetic axes lie along their major axes. Since the feedbelt ii ispositioned above the axis of symmetry of magnet 28, the particles areattractedtoward the upper pole 28, of this magnet and move toward it sopositioned that their major axes are coincident with the magnetic linesof force and thus the longitudinally oriented granules strike theadhesive coating on the underside of the material P and adhere theretoin an oriented position.

Since the web is closerto the pole piece 28 than it is to pole piece 29,invpassing out of-the concentrated end of the field the particles arecaused to assume a position such that their major axes are inclined tothe web because the web passes through a part'of the field where themagnetic lines are bent outward by reason of the concentration of thefield, as will be readily apparent from an examination of Figure 2. Themagnet is .also so positioned that the orienting lines of force at theconcentrated.end of the field are substantially vertical and thereforeinclined to the surface of the web. It is therefore possible to orientthe particles at any desired angle with respect to the web by suitablypositioning the web with respect to that part of the field where the webleaves the field. The angular position is maintained by rotating thesystem about the axis 40 to such an angle that the oriented, particlesare substantially normal to the earthand are therefore not displacedangularly by the force of gravity. The web is maintained in thisposition until the adhesive has been at least partially set by theaction of the air from the blower l8 whereupon it may be moved in anydesired direction without disturbing the orientation of the granularparticles.

The magnetized abrasive particles notonly impinge upon the adhesivecoating but are drawn into the adhesive by the continued action of themagnetic field and thus become more firmly em-, bedded therein. Whilethe abrasive particles may turn slightly as the coated web passesthrough the magnetic field the desired inclination of orientation isestablished by the angular relationship between the web and the lines offorce as the I web leaves the field.

Figure 3 illustrates, diagrammatically, the magnetic apparatus of Figure1 adjusted to orient the granular particles at a lesser angle vwithrespect to the web. The effect of making this adjustment in reducing theangularity of the inclination of the particles will be apparent from anexamination of the relative positions of the web P and the magneticlines of forces as represented by the dotted lines.

Figure 4 represents, on an enlarged scale, another form of magneticapparatus which is suitable for use where the granular material isweakly magnetic and it is impractical to construct one magnet to producea field i Will m 19- tensitytobothprojectandorientthegrains. This formof apparatus comprises a strong magnet 2! with upper and lower polepieces and 25 respectively, designed to set up a concentrated magneticfield positioned adjacent to the weaker end of a field of graduallyincreasing intensity of the type described in connection with Figure 1,set up by magnet 28.

In the operation of this form of apparatus the granulesare projected tothe web by the action of the field of magnet 22 while their angularitywith respect to the web is determined by reason of the action of thestrong part of the field of magnet 26. magnets it is possible to utilizegranular material which would otherwise be unsuitable.

Figure 5 is a diagrammatic illustration of a form of apparatus adaptedfor angularly orienting particles fed into the magnetic field fromabove. This apparatus comprises a magnet 12 with pole pieces 13 and 14designed to set up a distributed field, the weaker side of which ispositioned upward; idler rolls l8, l5, and magnetic roll IO for guidingan adhesive coated web into and through the magnetic field; a grain feedbelt 4| supported by the pulleys 42, 42a, 43 and 43a and positioned tofeed the granular particles into the magnetic field from above; and agrain dispensing device 35, 86 and I1.

In the operation of this apparatus granular particles, are fed into themagnetic field by the grain feed belt ll and upon entering the field areattracted toward pole piece 13 as a result of which they become embeddedin the adhesive on the surface of the web. Upon leaving the magneticfield the particles are oriented to an angular position with respect tothe .web by reason' of the fact that they assume positions with theirmajor axes parallel to the magnetic lines of force which are here cut bythe web at an angle. The web is then directioned downward at such anangle that the major axes .of the particles are substantially verticaland any disturbance of the orientation of the particles by reason ofgravity is thereby obviated.

In the operation of apparatus constructed as illustrated, the intensityof the magnetic field is adjusted to such a value that the granularparticles on the feed belt are propelled toward the pole piece andstrike the adhesive coating on the web P with suflicient force topartially embed themselves and adhere thereto. Other factors remainingconstant, we have found that the intensity required to magneticallypropel the charged granules into engagement with the adhesively coatedweb varies in proportion to the size or mass of the granules; that is, agreater intensity is required for the larger'grain than for smaller sizegrains. Thus, by changing the current flowing in the coils of theelectromagnets 28, 22 or 13 the magnetic intensity can be adjusted tosuch a value that grains of a certain specific size will be magneticallydeposited on the adhesivecoating, whereas any grains of a larger size,which might be present on the feed belt, will remain thereon and becarried into the bin 41.

In order to assure a uniform granular coating and to eliminatedifficulties with grain feed rolls we have found it desirable to apply asurplus of grain to the feedbelt ll. Different densities of graincoatings can be obtained by varying the current that energizes themagnet so that the lifting power of the magnet is increased As a resultof this combination of or decreased to raise more or less particles fromthe feed belt.

The pole pieces of the magnets may be adjusted so as to cause anydesired degree of orientation of the abrasive particles in such a mannerthat their longest dimensions are at some angle between 0 and preferablybetween 15 and 75, to the web to which they are attached.

Abrasive paper or cloth having the. abrasive grains so oriented has adifferent action depending upon the direction in which it is run. Forexample, a sanding belt made of such paper or cloth when run in thedirection of the inclination of the oriented particles may cut or abradevery rapidly while when run in the opposite direction, it has more of apolishing or finishing action. This is an advantage in that it ispossible to make one belt serve two purposes. 1

Not all granular materials are equally affected by magnetic forces,.somebeing readily affected and others being slightly afiected or requiringintense or highly concentrated forces to produce an appreciable effect.Apparatus constructed in accordance with our invention isreadily'adaptable to these different degrees of susceptibility and ispositive in action. When used with material that is readily susceptibleto magnetic forces, the-intensity of the field set up between the polesof the magnet can be adjusted to produce a granular coated web of thedesired characteristics. Adjustment of the intensity of the magneticfield to a higher concentration or greater density causes lesssusceptible particles to act in the same manner as more susceptibleparticles act in a lower intensity field.

The usual crushed granular abrasive materials contain some grains whichare elongated and some grains which are block-like. The elongated grainsmay be either in the form of needles or splinters in which one dimensionis materially longer than the other two dimensions, or'may be in theform of plates. This type of grain is susceptible of being oriented soas to produce thev than the other dimensions is susceptible of some.

orientation, depending upon the degree of elongation.

The present machine is adapted to operate upon the usual mixes and willeffectively orient the greater part, if not substantially all, of theelongated type of groin. However, if it is desired to produceabrasivecloth or paper having substantially all of the grains oriented, thematerial can .be subjected to separation of the elongated particles fromthe block-like particles, and this material used. It is found that airseparation tends to remove such particles from th block-like particles.V v

Thepresent machine, of course, is adapted to use only materials whichare susceptible to magnetic forces. Such abrasive materials contain ironimpurities and are naturally magnetic. Materials which in themselves arenot magnetic can be adapted for use by first coating them with anadhesive such as lacquer, varnish or the like, and then applying a thinlayer of some ironcontaining'magnetic material, to render themsusceptible to the magnetic orientation.

The machine is presusned to operate because stand out from the belt.

elongated magnetic particles, when passed into a magnetic fiield, act assmall magnets or doublets upon which the magnetic field has a strongorienting influence. The machine is particularly adapted for use onmaterials which are both magnetic and conductive, and which because oftheir electric conductivity have been difilcult to orient byelectrostatic means. The machine has certain advantages overthe'electrostatic type of orienting apparatus in that high voltages arenot required, but only those voltages usable for actuatingelectromagnets.

In our apparatus, the magnetized abrasive particles are not onlymagneticallyorlented but are magnetically projected from the feed beltonto the adhesive coated web. This is effective in securing the maximumdegree of orientation. The magnetized particles on the web, as they comeinto the magnetic field, will naturally tend to turn parallel to themagnetic field before they leave the belt. If not fully'turned beforethey leave the belt, they are still subjected to the turning influenceof the magnetic field as they travel freely from the belt to theadhesive coated surface. The result is that the particles as theyimpinge upon the adhesive coated surface are already oriented so thattheir longest dimensions This is far more effective in securing a highdegree of orientation than would be an attempt to apply the abrasivematerial by gravity in a haphazard manner and subsequently orienting theparticles.

The eifect of gravity in the application. of granular material to anadhesive coated surface is to tend to cause the elongated or plate-likeparticles to lie fiat against the adhesive coated surface. In ourapparatus, gravity does not tend to deposit the abrasive grains upon theadhesive coated surface, but on the contrary, the grains are drawnagainst the force of gravity and thereby tend to strike the adhesivecoated surface endwise. As shown in the drawings, any effect of gravityon a coated web which is carried in an inverted position during theinitial set of the [adhesive is to maintain the elongated particles intheir oriented position since they hang downwardly somewhat likependulums. As shown in Fig. 1, the adhesive is given a preliminary setsufficiently to hold the particles in their oriented position before theweb is passed over the roller 49 and into a vertical position.

The electric current employed for energizing the electromagnets mayeither be direct current or a pulsating current. When a pulsatingcurrent, such as an intermittent direct current, a rectified alternatingcurrent or even an alternating current, is employed, the length ofpulsations should be such as to effectively attract and orient themagnetic particles. I

Other advantages will be apparent from the foregoing disclosure tothoseskilled in the art and while specific embodiments have been used toillustrate our invention, it is to be understood that the invention isnot limited to those embodiments but is defined by the appended claims.

We claim:

1. Apparatus for the manufacture of granular coated. webs comprising apair of magnet poles positioned opposite one another, the adjacent facesof said poles being convergent toward one end, means for supporting andmoving an adhesive coated web between saidpole in a position closer toone pole face than the other and in the direction of convergency of thepole faces, the

positioned with respect to each other that the magnetic field at theconvergent end of the pole faces intersects the web at an oblique angle,and means for introducing granular material into the magnetic field andin proximity to the surface of the web that is more remote from the websupporting means.

2. Apparatus for the manufacture of granular coated webs comprising apair of magnet poles positioned opposite one another, the pole pieces ofsaid poles being broad toward their respective cores and narrow at theiradjacent edges, another pair of magnet poles positioned opposite oneanother and adjacent to the first pair of poles, the adjacent faces ofsaid second pair of poles being convergent toward one end which is moreremote from the first pair of pole pieces, means for supporting andmoving an adhesivecoated web between the pole faces of both pairs ofpoles in a position closer to the corresponding pole faces of the twopairs of=poles than to the other corresponding pole faces and in adirection from the first pair of poles toward the second pair of poles,the pole faces and web supporting means being so positioned with respectto each other that the magnetic field at the convergent end of the polefaces intersects the web at an oblique angle, and means for introducinggranular material into the magnetic field and in proximity to thesurface of the web that is more remote from the web supporting means.

3. Apparatus for the manufacture of granular coated webs havingparticles oriented at anoblique angle, comprising means for applyingmagnetically susceptible granular material to an adhesive coated surfaceof the web, means for producing a magnetic field, and means for passingthe granular coated web through the magnetic field and out of said fieldat an oblique angle to the magnetic lines of force thereof.

4. Apparatus for the manufacture of granular 'coated webs havingparticles oriented at an oblique angle, comprising means for producing amagnetic field, means for passing an adhesively coated web into saidfield, means located on the adhesive coated side of said web forintroducing magnetically susceptible particles into said field, magneticmeans for depositing said particles on said adhesive surface, and meansfor passing the 5. Apparatus for the manufacture of granular coated webshaving particles oriented at an oblique angle, comprising means forproducing a non-uniform magnetic field, means for passing an adhesivelycoated web into said field, a feed belt located on the adhesively coatedside of saidweb for introducing magnetically susceptible particles intosaid field,- said apparatus being adapted to deposit the granularparticles onto the adhesive surface and orient the particles at anoblique angle with respect to said web.

6. Apparatus for the manufacture of granular coatedv webs havingparticles. oriented at an oblique angle, comprising means for applyingmagnetically susceptible granular material to an adhesive coated surfaceof the web, means for producing a magnetic field having the magneticlines of force at one edge at least thereof substantially vertical, andmeans for passing a granular coated web with its coated face downwardlythrough such magnetic field at an oblique angle to the horizontal, thedirection of travel being such that the web emerges from said field at apoint where the magnetic lines of force are substantially vertical,whereby the force of gravity, tends to hold the particles in asubstantially vertically oriented position and at an oblique angle tothe surface of the web.

7. Apparatus for the manufacture of granular coated webs havingparticles oriented at an oblique angle, .comprising means for producinga substantially vertical field, means for applying magneticallysusceptible granular material to the adhesive coated surface of the weband means for passing the web with its coated face downwardly throughsaid field at an oblique angle to the horizontal, whereby themagnetically susceptible particles are oriented at an oblique angle tothe web, and means for passing the web having the particles so orientedthrough a. drying zone and out of contact with devices which woulddestroy such orientation of the particles until the adhesive has set.

' HENRY P. KIRCHNER.

ROMIE L. MELTON. RAYMOND C. BENNER.

